/* mockturtle: C++ logic network library
 * Copyright (C) 2018-2019  EPFL
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use,
 * copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following
 * conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */

/*!
  \file stopwatch.hpp
  \brief Stopwatch

  \author Mathias Soeken
*/

#pragma once

#include <chrono>
#include <iostream>
#include <type_traits>

#include <fmt/format.h>

namespace mockturtle {

/*! \brief Stopwatch interface
 *
 * This class implements a stopwatch interface to track time.  It starts
 * tracking time at construction and stops tracking time at deletion
 * automatically.  A reference to a duration object is passed to the
 * constructor.  After stopping the time the measured time interval is added
 * to the durationr reference.
 *
   \verbatim embed:rst

   Example

   .. code-block:: c++

      stopwatch<>::duration time{0};

      { // some block
        stopwatch t( time );

        // do some work
      } // stopwatch is stopped here

      std::cout << fmt::format( "{:5.2f} seconds passed\n", to_seconds( time )
 ); \endverbatim
 */
template <class Clock = std::chrono::steady_clock>
class stopwatch {
  public:
    using clock = Clock;
    using duration = typename Clock::duration;
    using time_point = typename Clock::time_point;

    /*! \brief Default constructor.
     *
     * Starts tracking time.
     */
    explicit stopwatch(duration& dur) : dur(dur), beg(clock::now()) {}

    /*! \brief Default deconstructor.
     *
     * Stops tracking time and updates duration.
     */
    ~stopwatch() { dur += (clock::now() - beg); }

  private:
    duration& dur;
    time_point beg;
};

/*! \brief Calls a function and tracks time.
 *
 * The function that is passed as second parameter can be any callable object
 * that takes no parameters.  This construction can be used to avoid
 * pre-declaring the result type of a computation that should be tracked.
 *
   \verbatim embed:rst

   Example

   .. code-block:: c++

      stopwatch<>::duration time{0};

      auto result = call_with_stopwatch( time, [&]() { return function(
 parameters ); } ); \endverbatim
 *
 * \param dur Duration reference (time will be added to it)
 * \param fn Callable object with no arguments
 */
template <class Fn, class Clock = std::chrono::steady_clock>
std::invoke_result_t<Fn> call_with_stopwatch(typename Clock::duration& dur,
                                             Fn&& fn) {
    stopwatch<Clock> t(dur);
    return fn();
}

/*! \brief Constructs an object and calls time.
 *
 * This function can track the time for the construction of an object and
 * returns the constructed object.
 *
   \verbatim embed:rst

   Example

   .. code-block:: c++

      stopwatch<>::duration time{0};

      // create vector with 100000 elements initialized to 42
      auto result = make_with_stopwatch<std::vector<int>>( time, 100000, 42 );
   \endverbatim
 */
template <class T, class... Args, class Clock = std::chrono::steady_clock>
T make_with_stopwatch(typename Clock::duration& dur, Args... args) {
    stopwatch<Clock> t(dur);
    return T{std::forward<Args>(args)...};
}

/*! \brief Utility function to convert duration into seconds. */
template <class Duration>
inline double to_seconds(Duration const& dur) {
    return std::chrono::duration_cast<std::chrono::duration<double>>(dur)
        .count();
}

template <class Clock = std::chrono::steady_clock>
class print_time {
  public:
    print_time() : _t(new stopwatch<Clock>(_d)) {}

    ~print_time() {
        delete _t;
        std::cout << fmt::format("[i] run-time: {:5.2f} secs\n",
                                 to_seconds(_d));
    }

  private:
    stopwatch<Clock>* _t{nullptr};
    typename stopwatch<Clock>::duration _d{};
};

} // namespace mockturtle
